Pulse-time telemetering system



Qt. lo, 195o M. c. PoYLo 2,524,832

PULSE-TIME TELmaETERmG sysma Filed April 6, 194e v E .f i V: f :L i 8 232mb ze 41/ wil ms- L MITTER v6a /59 .8 manuel l Raaf/vf@ maknmer 64T M 65 effi-Zr 61 A TTOR/VE Y Patented oct. io, leso PULSE-TIME TELEMETERING SYSTEM vMichel C. Poylo, New York, N. Y., asslgnor to Federal Telecommunication Laboratories,

Inc.,

New York, N. Y., a corporation of Delaware ApplcationApril 6, 1946, Serial No. 660,103

This invention relates to rality of diierent meters is simultaneously transmitted to .one or a plurality of points by means of electronic distributor devices.

a telemetering sys-V tem. Moreparticularly it deals'with a telemetering system in which the intelligence from a plu- 2 claims. (ol. 177-351) Generally speaking the telemetering system of .this invention comprises the following three es- Itis an object of this invention to transmit intelligence -from meters to remote points in a novel and effec/tive manner.

It is anotherv object to transmit and receive intelligence from meters over a, .high frequency electromagnetic carrier Wave.

It is another` object toftelemeter the intelligence from a plurality of meters continuously and simultaneously.

It is another object to telemeter the intelligence from a plurality of meters continuously and simultaneously by means of electronic distributor devices such as cathode ray tubes.

It is. another object to telemeter the intelligence from a plurality of meters continuously and simultaneously over a single radio frequency wave band. y

It is another object to telemeter the intelligence from meters by pulses of high repetition rate on an electromagnetic Wave.

It is another object to telemeter intelligence from a plurality of meters continuously and simultaneously by means of time modulated pulses on an electromagnetic wave. l Y

It is another object to telemeter intelligence from a plurality of different types of meters either mechanical or electrical or both continuously and simultaneously.

It is another object to telemeter intelligence from meters in vehicles which may be attended or unattended such as aircraft, Weather balloons, missiles and the like, so that their speeds, temperatures, pressures and other conditions including location, altitude and the like, may be indicated at one or a plurality of points which may be either` movable or fixed.

It is another object vcontinuously and simultaneously to record intelligence from a plurality of meters which are located at a distant point, which point may be on a vehicle such as an airplane on a test flight. Thus, `by means of this invention a complete record of the conditions within a plane may be recorded during a test flight untilrits termination, including termination by a crash resulting in the destruction of the instruments andl meters on the plane and otherwise loss of their records.

Still other objects and features of this invention will appear from time to time in the description which follows.`

sential steps:

(l) `means to convert meter indications Vinto corresponding changes in an electrical wave for modulation of pulses on an electromagnetic wave;

(2) means to transmit said pulses to a distant point; and

(3) means to receive the modulated pulses-and convert them to reproduce the indications of the original meter.

The rst essential element, may comprise any suitable means for converting the indications of the meter or meters into corresponding changes in an electrical wave. In the case of an electrical meter, it may be directly coupled to the converting means for transmitting these changes. In the case of a mechanical meter, it may comprise means for following the needle or indicator of the meter and converting the motion thereof into electrical changes, or means coupled to a movable part of the meter 'for converting its motion into changes in an electrical wave. These changes may be changes in the amplitude of the voltage 'or current, or frequency, or the like. The resulting changes in electrical Wave are then employed for controlling an electronic distributor which may comprise a cathode ray beam deected by said electrical changes to produce correspondingly modulated pulses. These pulses may be modulated in amplitude, frequency, or time, the latter being preferred.

The second essentia1 element of this system is the means for transmitting these resulting pulses over a suitable medium either directly, if their repetition rate is suiciently high, or by modulation on an ultra-high frequency electromagnetic wave. These pulses may be transmitted by radio or through a coaxial cable or the like, as desired.

e third essential element of this system is the means for the reception of the modulated transmitted pulses and their demodulation for reproducing the indications of the original meter or meters. The received modulated pulses are demodulated in an electronic distributor device which may include a cathode ray beam, the deection of which beam may be controlled by the pulses to reproduce corresponding changes in an electrical wave. These changes may then be applied to any well-known metering device, such as the voltmeter or a frequency meter (depending upon the types of changes produced in the electrical Wave) for reproducing the indications of the original meters.

If a plurality of different types or similar meters are located at one point all of whose indications it is desired simultaneously and continuously to transmit to another point or points, separate trains of modulated pulses maybe produced from each one of the meters and these trains may be interleaved on a single multichannel pulse wave, similar groups of pulses being separated .by a synchronizing signal or pulse, and transmitted over a single ultra-highv frequency carrier wave band. A singlevcathode ray electronic distributor device may be employed for modulating the changes in electrical waves from a plurality of different meters. Such a distributor device is disclosed in the cooending apolications of E. Labin and D. D. Grieg Serial No. 591,065, iiled Anril afl, 1945. Patent No. 2.429.631, October 28, 1947, and Serial No. 567.414, illed December 9, 1944, Patent No. 2,495.738. Similarly, a single electronic distributor device may be used for'the simultaneous separation end demodulation of the given trains of modulated pulses, corresponding to each of the meters, by deiiection and synchronization of a cathode ray beam in a device of the type disclosed in the copending application of F. l-ahin and l). n. Grieg. Serial l`To. 565.152. filed November 25. 1944. now Patent No. 2,465,380, issued Merch 29. 1949.

By employing a relatively high repetition rate of pulses such as for examnle, about 8.000 pulses per second, a large number of different meter indications may be transmitted from each meter each second. thereby enabling the. reproduction of a substantially continuous and simultaneous record oi all of said meters. However, such a high pulse repetition rate is generallv not necessary and a. much lower repetition rate mey be employed without visuallv changing the desired reproduced indications. Thus, the .indications of la plurality of meters may be scanned manv times each second to give a substantiel continuous indication of all of these meters at anv desired remote point. Some meters may reduire a different pulse repetition rete i. e. a wider frequency hand for transmission of their indications than others. For exemnle, changes in voltage may be transmitted at a much lower rete than changes in frequency, so that several indications from different meters producing changes in voltage amplitude mey be transmitted while changes in freouencv from one of the other types of meters are being transmitted. In such a case, separate cathode rey electronic switching deviees of the tvne mentioned in the above natents may be multiplexed similarlv to those shown and described in the conending application of E. Labin and D. D. Grieg, Serial No. 632,731, filed December 4. 1045.

These and other features and ohlects of this invention will become more apparent woon consideration of the following detailed deserintion' of an embodiment of this invention to be read in connection with the accompanying drawings, in which:

Fig. 1 is a schematic blockwiring diagram of a telemeter transmitter station according to this invention;

Fig. 2- is a graph of wave-forms explaining the operation of Figs. 1 and 3: and

taneously transmitted and reproduced at a dis-A tant point.

Referring to Fig. l, there is shown a plurality of meters I. 2, 3 and I. each of'which is vshown with a different type of means for converting their indications .into corresponding changes in an electrical wave. Meter I is herein considered to be an electrical meter wherein the energy for operating lthe indicator thereon is electrical energy and may be directly withdrawn from the meter across a suitable resistance 5 through line 8 to the electronic distributor device 9 (described later). If the transmission station shown in Fig. 1 were on an airplane, the electrical meter I could be an electrical temperature gauge. gasoline gauge, carburetor-mixture temperature gauge, oil temperature gauge, an ammeter, a voltmeter, an electronic altimeter. an electric ilap or landing gear position indicator, or the like.

L If desired any one or all of these gauges' may be electrically connected to the device 3; each meter having reserved to it a separate communication channel, hereinafter referred to as channels a, b, c. d 11.. These meters are shown identified with these channels both in the transmitting and receiving stations for the purposes of comparison.

Meters 2, 3 and Il may be electrical meters also, or they may be mechanical meters, which'. on an airplane, could be tachometers, air speed meters, barometric altimeters, artificial horizon gauges, gyro compasses, 'oil pressure gauges, iuel pressure gauges, or hydraulic iiap and landing gear indicators, and the like.

The type of means shown for converting the movement of meter 2 is one which may be clamped onto the outside of the dial or cover glass of the meter 2 by a suitable means, such as a suction cup Iii, having pivotally mounted thereon an arm II with an electromagnet I2 at the end thereof to follow the end of the pointer I3 of the meter 2. On the arm II is also anelectric contact I4 which slides over an electrical resistance element I5 to change the amount of voltage drop through this element -I5 in accordance with the positon of the pointer or indicator on the meter 3. One end of this resistance being coupled to the battery I6, and the other end to contact Il through iiexible connection I'I- and line I3 to the distributor device 3.

Meter 3 coupled to channel c, has mounted on the needle 20 thereof, a seml-crescent-shaped y the current through the coil 23 of the magnet,

corresponding to the width of the portion of the crescent-shaped conductor 2| which is inserted between the poles of the magnet 22. Thecircuit through the coil 23 is from battery on the one side and through line 21 to the distributor device 9, on the other side.

'Ihe meter I, corresponding to channel d, is coupled to convert its movements by variations in frequency of the electrical wave applied to the device 9. Herein, the indicator or needle 28 of the meter 4 has mounted thereon a semi-crescent-shaped conductor 29 (similar to 2i mentioned above) which moves longitudinally between a pair of coils 30 in e. circuit with a condenser 3I which circuit is coupled through line 32 to an oscillator 33. The various positions of the needle 2liI and corresponding various widths Qf the QOIldllCliOr 29 between the coils III, changes thetime constant ofthe circuit comprising coils 30 and condenser 3|, thereby changing the .fre-

quency of the Ollput of the oscillator 33. These' are frequency variations.

The particular electronic distributor device 9 Idescribed herein is known as a Cyclodos type of cathode ray tube. In this device, the sweep of the cathode ray beam around the target end of the tube is shown to be circular.- ThisI beam is formed at the cathode 31, controlled by grid 38 and caused to ro-tate by being deected by the changes on the vertical and horizontal plates 39 and 40, respectively, coupled to the sweep circuit 4| energized by the base wave generator 42,

such'as a sine wave generator. In such a case,

the sweep circuit 4I comprises means for produclng two sine waves 90 out of phase with each other, one of which is applied to the vertical plate 39 and the other to the horizontal plate 49.

Thus, the electron beam is caused to rotatearound the segmenting plate 43 having apertures 1 44 therein which divide the beam up into segments. Aligned with each these segments are deflection plates 45, one corresponding to each signal channel. Deecting plates 45 are arranged around a central electrode 46, the potentials between electrodes 45 and 46 being such that the changes in the electrical waves in the lines 8. I9, 21 and 36 will correspondingly cause the bea'n to be deflected radially proportionally to the magnitude of said changes. The resulting deflected segments of the beam impinge upon the target plate 41 having angularly disposed slots 48 therein, one slot corresponding to each of said plates 45 or channels a, b, c, d n. At the top of plate 41 there are a pair of slots 49 for which there is no corresponding deflection plate 45 adjacent the previous mentioned electrode 46. These slots 49 produce a pair of closely-spaced pulses which may be used as synchronizing pulses S, shown on the Wave 50 in Fig. 2. The angularlydisplaced slots 48 are so shaped that they will cause the segments of the beam to be modulated in time with respect to the position of the synchronizing-pulses S from slots 49 due to their deflection by means of the energy applied to the deflecting plates 45. Behind the aperture plate 41 is shown a collector electrode 5I from which the separate pulses of energy caused by the passage of the beam `through the separate apertures in plate 41, are collected and passed through line 52 to a cathode-follower circuit 53. Thence these pulsesnow as wave 50, are passed through line 54 to a suitable transmitter 55, which may be a radio transmitter coupled to an antenna 56.

Referring back to wave 50, it is seen that each one of the signal channels a, b, and c (corresponding to the meters I, 2 and 3) comprises pulses of energy which are time modulated in one direction with respect to the fixed position of the synchronizing pulses S on said wave, Pulse d, however, which is frequency modulated may be modulated in both directions. If desired, the synchronizing pulses S may be replaced by a single wide pulse or any other suitable shaped pulse lto distinguish' it from the time modulated pulses a, b, c, d n. The repetition rate of the synchronizing pulses S is identical with that of the rotation of the beam around the device 9, and with the frequency of the sine `wave 51 generated in the base wave generator 42.

Referring now to a receiverstation shown in Fig. 3, which is located at the' point or at one of the points, where the indications of the meters are to be reproduced, there is provided an antenna 58 which is coupled to a suitable receiver 59 from which is withdrawn through line 60 a wave, similar to wave in Fig. 2, which may be passed into a suitable synchronizing pulse separator circuit 6l for separating the synchronizing pulses S from the remaining pulses on the wave 50. The synchronizing pulse separator or selector circuit 6| may be a width selector circuit if the synchronizing pulse' is a wide pulse, or it may be a circuit for superimposing and clipping the S pair of pulses on the wave 50 for producing a pulse wave in accordance with the disclosure in the copending application of D. D. Grieg, Serial No. 625,650, filed October 30, 1945, now Patent No. 2,485,591, issued October 25, 1949. The thus separated synchronizing pulses S may be passed from the separator '6I through line 62 into a suitable sine Wave generator 63 which is coupled through line 64 to a sweep circuit 65 (similar to circuit 4I) which in turn is coupled to the vertical and horizontal deflection plates 66 and 61, respectively, of the cathode ray electronic distributing device 68. This distribulting device 68 is known as a lCyclophon and may be of the type described in the copending application of E. Labin and D. D. Grieg, Serial No. 565,152, led November 25, 1944, now Patent 2,465,380, issued March 29. 1949. This particular cathode ray electronic distributor device 68 is provided with a cathode 69 for producing a. beam of electrons which is cut olf and on by applying to the grid 10 thereof the pulses of wave 50 through lines 80 and 1I and condenser 12 from receiver 59. The beam formed at the cathode 69 is rotated around the apertures 13 in the target plate 14 by means of two sine waves, similar to wave 51 but 90 out of phase with each other, which are applied to the plates 66 and 61. Since these waves are formed from the Wave from generator 63 which in turn was formed from the synchronizing pulses S on wave 50, the rotation of the beam in device 68 is in synchronism with the rotation of the beam in device 9. Thus, the time when the beam is cut off and on by the time modulated pulses a, b, c, d

n causes the electrons in the beam segments to cover different areas 15 of the apertures 13 on the target 14. Behind each one of the apertures 13 are positioned separate target electrodes 16, one corresponding to each of the signal channels a, b, c, d n and corresponding to each of the apertures 13 on plate 14. By covering different areas of said target electrodes 16, pulses of different amplitudes are derived dependent upon the amount of overlap of the electron beam of said electrodes. The combination of the plate 14 and the target 16 form an anode-dynode outputting arrangement which has the advantage of increasing the sensitivity over that which would be obtained if only separate target plates 16 were `employed and shaped so that only the desired areas 15 of the segmented beams would fall on them.I Connected to each of the targets 16 through line 11 are suitable lters 18 for integrating the output pulses and converting the resulting different amounts of electrons or amplitude demodulated pulses of energy into a comparatively low frequency wave for operating suitable indicators or meters for reproducing the indications ofthe original meters I, 2. 3 and l. The United States Patent No. 2,438,928 gives an example of .how variable amplitude pulses may be converted into low frequency waves by means of simple low pass filters as outlined in the previous sentence hereof.

Corresponding to the meters I, 2 and I from whichls obtained amplitude energy in Fig. 1, there may be voltmeters 19, 80 and 0| having scales calibrated to indicate readings identical with said meters i, 2 and 3. Since the energy over channel .d is frequency modulated, the impulses received on target 'I0 corresponding thereto is also frequency modulated and may be passed through a lter 18 before it is passed through line I2 to 'a frequency meter 83, which may be calibrated for reproducing the identical readings of the meter 4 in Fig. 1. If desired, instead of the meters 19, 80, 8i, and 03 there may be used recording meters for recording all of the indications of the meters I, 2, I and 4 over a given period of time.4

Similarly, many other meters may be placed over other channels and coupled through the electronic distributing devices 9 and as described abve.v I

While the above is a description oi' the principles of this invention in connection with specific apparatus and particular modiilcations thereof, it is to be clearly understood that this description is made only by way of example and not as a limitation on the scope of this invention as de- 'ned in the objects and the accompanying claims.

I claim:

1. Meteorological apparatus which comprises means for transmitting reference pulses several times each second at a xed rate of repetition, means for' transmitting intelligence signals between each pair of reference pulses, the time between a reference pulse and each succeeding intelligence signal being a function oi' a meteorological condition, a receiver for said pulses and signals, means associated with said receiver for continuously converting the elapsed time between said reference pulses and each intelligence signal into an electrical value proportional to the elapsed tinlie, and means Vfor continuously recording said va ue.

2. Meteorological apparatus which comprises means for transmitting reference pulses several times each second at a ilxed rate o1' repetition, means for transmitting intelligence signals between each pair oi reference pulses, the time between a reference pulse and each succeeding intelligence signal being a function of a meteorological condition, a receiver for said pulses and signals, means associated with said receiver for continuously converting the elapsed time between said reference pulses and each intelligence signal into a voltage value proportional tothe elapsed time, and means for continuously recording said value.

MICHEL C. POYLO.

REFERENCES CITED 'Ihe following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,620,405 Sprenger Mar. 8, 1927 2,057,773 Finch Oct. 20, 1936 2,199,634 Koch May 7, 1940 2,378,395 Dickson June 19, 1945 2,381,920 Miller Aug. 14, 1945 2,400,170 Silverman May 14, 1946 2,403,890 Johnson July 9, 1946 

